Submersible power plants are known in the art. One kind of submersible power plants uses a vehicle comprising a wing. The vehicle is arranged to be secured to the structure by means of a tether and is arranged to move in a predetermined trajectory by means of a fluid stream passing the vehicle. The control of the vehicle depends on input from sensors which provide information on various parameters needed to control the vehicle. This is described in EP 1816345.
One application for a submersible power plant is the production of electricity from a fluid stream, such as a tidal stream, by allowing the energy of a fluid stream to be converted to electrical energy by for instance a turbine and generator being placed on the vehicle.
The use of a tidal stream for producing electricity gives rise to a number of situations wherein the vehicle needs to be controlled in order to be able to start and stop the vehicle during normal operation and to be able to control start and stop of the vehicle to avoid damage to the vehicle. Further, it is desirable to optimise the power output of the power plant during normal operation.
There thus exists a need for an improved method and power plant for controlling the operation of a submersible power plant in various vehicle states.